Servicing devices for vehicle air-conditioning systems serve inter alia to empty from time to time within a maintenance operation the refrigerant circuit of the most varied of vehicle air-conditioning systems and to introduce a new fill of refrigerant. It is necessary here to comply with precise quantities and refrigerant specifications. In addition, in many cases lubricating oil for the compressor of the refrigerant circuit must be removed from the vehicle air-conditioning system and replenished again. This also takes place in quantities and specifications dependent on the type of vehicle or respectively type of air-conditioning device. Some vehicle air-conditioning systems also require an additive for the refrigerant circuit, which during a maintenance service is likewise partially replaced. Usually, the compressor oil arrives into the refrigerant circuit and is therefore also pumped around during the operation of the air-conditioning systems. Only quite specific pairings of refrigerant and compressor oil are compatible with one another for this purpose. In order to be able to recover at least a portion of the refrigerant for re-use after the drawing off of the refrigerant/compressor oil mixture, service devices for vehicle air-conditioning systems usually also have a separator by which refrigerant can be separated from the refrigerant/compressor oil mixture for re-use. Used compressor oil and, if applicable, used additive, is/are generally collected by the servicing device in order generally to be subsequently discarded.
As illustrated in applicant's WO 2007/0845480, there is a servicing device for vehicle air-conditioning systems that is known according to the block diagram and FIG. 1. The patent application shows in a continuous line the essential components of the generic servicing device for a vehicle air-conditioning system and, in dashed lines, a vehicle air-conditioning system which is to be serviced. The latter consists of compressor 1′ which is lubricated by oil, a condenser 2′, a vaporizer 3′ and, between these components, pipelines 4A′-4C′ producing a closed coolant system. In addition, a dryer 5′ is provided, which can also serve as a collector or reservoir for refrigerant. Finally, two servicing connections 6A′/6B′ are installed into the refrigerant circuit for the fluid exchange. The cold which is available at the vaporizer 3′ is discharged by a cold air blower 7′ and supplied to the interior of the vehicle. The condensation heat of the condenser 2′ is transported away by a warm air blower 8′. Servicing connection connectors 9A′ and 9B′ of a servicing device 20′ permit, in the case of servicing, refrigerant/compressor oil mixture to be extracted or respectively filled at the servicing connections 6A′, 6B′. The vehicle air-conditioning system, numbered as a whole by 10′ differs from vehicle type to vehicle type and is not the subject matter of the present invention.
A servicing device designated as a whole by 20′ for a vehicle air-conditioning system has flexible pressure hoses 11A′, 11B′ for connecting the servicing device 20′ with the vehicle air-conditioning system 10′ via the servicing connection connectors 9A′, 9B′ at the servicing connections 6A′, 6B′. A suction pump 12′, constructed as a refrigerant compressor, conveys used refrigerant/compressor oil mixture via the pressure hoses 11A′ and 11B′ and a separator 14′. The latter separates refrigerant from the drawn-off mixture by vaporization and feeds this to a refrigerant reservoir 15′ which is constructed as a pressure container. Compressor oil/additive mixture which is precipitated in the separator 14′ is collected in an exchangeable used oil container 16′ and its weight is determined by means of weighing device 17A′. An air-cooled refrigerant condenser 15A′ is securely connected with the refrigerant reservoir 15′. Thereby, refrigerant which is fed back is fed predominantly in liquid form to the refrigerant reservoir 15′. The entire refrigerant reservoir together with condenser rests on a further weighing device 17B′ for detecting the refrigerant which is fed in and discharged and also that which is in store. After the drawing off of the used mixture, a vacuum pump 13′ provides for the negative pressure necessary for the refilling in the circuit of the vehicle air-conditioning system and discharges the drawn-off gas volume e.g. to the atmosphere.
A refilling system designated as a whole by 19′ consists substantially of exchangeable storage containers 19D′ for compressor oil and 19C′ for additives, a control unit 19A′ with valve block and control lines 19B′, a remote display 19E′ and metering- and valve units 19F″ to 19F″″. The storage containers 19C′ and 19D′ are preferably able to be weighed. Further weighing devices 17C′, 17D′ serve for this.
As illustrated in DE 20 2008 003 123 U1, there is a further servicing device for vehicle air-conditioning systems of the applicant that is known, in which the refillability of the previously evacuated vehicle air-conditioning system is improved by a heat source provided in the refrigerant storage container to increase the pressure of the refrigerant. A comparable servicing device for vehicle air-conditioning systems is known from US 2009/0158756A1.
In a further generic service device for vehicle air-conditioning systems of the applicant, it is known from the still unpublished DE 10 2009 054 446, applied for on 25 Nov. 2009, in a first servicing phase to draw off a circuit mixture of refrigerant, compressor oil and, if applicable, further mixture components, from a vehicle air-conditioning system into a separator stage by means of a refrigerant compressor via a separator and, in so doing, to separate refrigerant by means of the separator from the drawn-off circuit mixture, to compress it and collect it and to determine its quantity. In a second servicing phase, the refrigerant circuit system of the vehicle air-conditioning system is largely residually emptied by means of a vacuum pump. Residual gases which are pumped out in the second servicing phase are directed by means of the refrigerant compressor through the separator stage and the quantity of the refrigerant residue which is collected thereby is determined. Through this step, inter alia the diagnosis of the status of the vehicle air-conditioning system is improved. Residual gases arrive if necessary in purified form into the atmosphere.